8173715: Remove FlatProfiler
Summary: Obsoleted Xprof flag, removed FlatProfiler code
Reviewed-by: dholmes, coleenp, vlivanov, pliden

8155992: Change name of StealRegionCompactionTask to something that emphasizes the compaction task.
Reviewed-by: kbarrett, ehelin, drwhite

8150994: UseParallelGC fails with UseDynamicNumberOfGCThreads with specjbb2005
Reviewed-by: tschatzl, kbarrett

8079792: GC directory structure cleanup
Reviewed-by: brutisso, stefank, david